Up to now, an applicator that holds a microneedle array by means of a latch mechanism or the like has been known, the microneedle array including a large number of microneedles each having a leading end to which a medical agent or the like is applied (see Patent Literatures 1 to 5). If the microneedle array held by the applicator is caused to collide against a skin by disengaging the latch mechanism, the microneedles are stuck into the skin, and active ingredients contained in the medical agent or the like are transferred into the body of an animal (for example, a human) through the skin.